The Georgetown waterfront is one of the oldest areas in the Washington region. Over the years it has experienced evolving periods of commercial prosperity and urban blight. Today it is a park.
These heaps of sandstone in the heart of Rock Creek Park used to be a part of the Capitol Building. They were taken down in 1958 when the east front was expanded and rebuilt in marble.
The National Park Service has jurisdiction over Washington's many parks, plazas and traffic circles. They got into a nasty bureaucratic turf war with WMATA in the 1970's as Metro was being built.